Industrial Field of the Invention and Description of the Related Art
This invention relates to a stereo endoscope apparatus which is able to stereoscopically observe the portion to be observed.
Recently, endoscopes have been widely used for observing the coelom, internal organs and so forth. In use, an elongated insertion portion thereof is inserted into the coelom or the inner parts of internal organs to observe the coelom or the internal organs, or various types of medical treatment to be performed with the aid, if necessary, of a treatment tool that is inserted into the treatment tool channel thereof, or to observe or treat the inside portion of various mechanical devices.
However, the conventional endoscope can only observe the item to be observed, for example, a coelom, in the form of a planar object, without perspective. It therefore involves a problem in that, for example, it is difficult to observe any slight unevenness on the surface of a coelom, which is a very important factor as a diagnosis index. In order to solve this problem, an art designed to observe the coelom was disclosed in Japanese Patent Laid-Open No. 69839/1982 in which a pair of image guides is inserted into an insertion portion of an endoscope, the image guide having an objective lens at one end thereof and an ocular at the other end thereof, and the convergence angle formed by the pair of the objective lens and the subject point to be observed is made to be such that the subject point can be observed stereoscopically. However, in this art, the outer diameter of the insertion portion of the endoscope is made too large, causing patients to suffer some discomfort. The outer diameter of the endoscope is preferably as small as possible in order to reduce the sensation of discomfort experienced by a patient and to allow the observer to observe the isthmus of the coelom.
When any unevenness on the surface of a subject (organism) is to be measured, a scale is used, as disclosed in Japanese Patent Publication No. 20488/1986, in such a manner that the scale is applied to the subject. Another method is disclosed in Japanese Patent Laid-Open No. 110208/1980 in which laser beams are used.
According to the prior art disclosed in Japanese Patent Publication No. 20488/1986, since it is necessary for the subject and the scale to be brought into contact with each other, there is potential for the organism to be injured, and the endoscope is difficult to handle. Furthermore, since the allowable range that can be measured is a single point, it has been difficult to conduct wide range measurements.
On the other hand, according to the prior art disclosed in Japanese Patent Laid-Open No. 110208/1980, it is necessary for a special apparatus such as a laser beam to be instituted; otherwise measurement can only be conducted in units equivalent to the distance between light spots, and sufficient resolution cannot therefore be obtained. Furthermore, a problem arises in that normal observation is interfered with by the laser beams.